The present invention concerns ad-hoc networks and in particular a protocol for manipulating session endpoints in an ad-hoc network environment.
Recent advances in wireless communication technologies coupled with increased capabilities and decreased cost of computer technology have enabled wireless computing applications that had previously been either prohibitively expensive or too bulky for portable devices. Many such applications may be built on a network structures known as mobile ad-hoc networking (MANET). Ad-hoc networks are formed dynamically using groups of mobile computing nodes that have changing connectivity. To operate efficiently, it is desirable for these networks to include the routing functions in each node. Due to the short-range nature of these devices, a communication channel between devices may traverse several intermediate nodes between its source and destination. Because each traversal is known as a “hop,” these networks are referred to as multi-hop networks.
By implementing routing functions in the nodes, these networks allow quick reestablishment of paths between two connecting nodes if an intermediate node can no longer be a part of the network. If, for example, one path between communicating nodes disappears because a device used for one of the hops is no longer able to communicate with other nodes in the group, a secondary path that does not need the missing node may be quickly defined.
Many possible protocols have been defined to implement ad-hoc networking. These include Ad hoc On-Demand Distance Vector (AODV) Routing, Dynamic Source Routing, Optimized Link State Routing and Topology Broadcast Based on Reverse Path Routing. All of these protocols are described on a web-site maintained by the Mobile Ad-Hoc Network working group of the Internet Engineering Task Force (ITEF).
To date, mobility management has been largely concerned with two problems: handoff management and location management. Handoff management concerns the maintenance of an active session between a mobile node and a correspondent node in a mobile network while the mobile node is moving. When a mobile node leaves the coverage area of its current base station and enters the coverage area of a new base station, handoff between the current base station and the new base station keeps the session active. This problem is addressed by existing protocols, such as the Mobile IP protocol described in RFC 2002.
Location management concerns the problem of locating a mobile node in a network when it is not actively communicating. This may be desirable when, for example, the network receives an incoming call, directed to the mobile node. To solve this problem, the network finds a base station having a coverage area that includes the mobile node. The location management problem has been addressed in IETF protocols, for example, the Mobile IP protocol, referenced above.